\documentclass[border=5pt]{standalone}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture}
    \begin{axis}[
        minor tick num=4,
        enlarge x limits={
            abs=0.20,   % <-- minor ticks larger than last major tick are not drawn
%            abs=0.25,   % <-- minor ticks larger than last major tick are drawn
        },
    ]
        \addplot table {
            x    y
            0.0    100
            1.5    10
        };
    \end{axis}
\end{tikzpicture}
\end{document}